/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.extensions.gcp.util;



import com.google.auto.value.AutoValue;



import java.io.Serializable;

import java.util.ArrayList;

import java.util.List;



/**

 * An optional component to use with the {@code RetryHttpRequestInitializer} in order to provide

 * custom errors for failing http calls. This class allows you to specify custom error messages

 * which match specific error codes and containing strings in the URL. The first matcher to match

 * the request and response will be used to provide the custom error.

 *

 * <p>The intended use case here is to examine one of the logs emitted by a failing call made by the

 * RetryHttpRequestInitializer, and then adding a custom error message which matches the URL and

 * code for it.

 *

 * <p>Usage: See more in CustomHttpErrorsTest.

 *

 * <pre>{@code

 * CustomHttpErrors.Builder builder = new CustomHttpErrors.Builder();

 * builder.addErrorForCodeAndUrlContains(403,"/tables?", "Custom Error Msg");

 * CustomHttpErrors customErrors = builder.build();

 *

 *

 * RetryHttpRequestInitializer initializer = ...

 * initializer.setCustomErrors(customErrors);

 * }</pre>

 *

 * <p>Suggestions for future enhancements to anyone upgrading this file:

 *

 * <ul>

 *   <li>This class is left open for extension, to allow different functions for HttpCallMatcher and

 *       HttpCallCustomError to match and log errors. For example, new functionality may include

 *       matching an error based on the HttpResponse body. Additionally, extracting and logging

 *       strings from the HttpResponse body may make useful functionality.

 *   <li>Add a methods to add custom errors based on inspecting the contents of the HttpRequest and

 *       HttpResponse

 *   <li>Be sure to update the HttpRequestWrapper and HttpResponseWrapper with any new getters that

 *       you may use. The wrappers were introduced to add a layer of indirection which could be

 *       mocked mocked out in tests. This was unfortunately needed because mockito cannot mock final

 *       classes and its non trivial to just construct HttpRequest and HttpResponse objects.

 *   <li>Making matchers composable with an AND operator may simplify enhancing this code, if

 *       several different matchers are used.

 * </ul>

 *

 * <p>

 */

public class CustomHttpErrors {



  /**

   * A simple Tuple class for creating a list of HttpResponseMatcher and HttpResponseCustomError to

   * print for the responses.

   */

  @AutoValue

  public abstract static class MatcherAndError implements Serializable {

    static MatcherAndError create(HttpCallMatcher matcher, HttpCallCustomError customError) {

      return new AutoValue_CustomHttpErrors_MatcherAndError(matcher, customError);

    }



    public abstract HttpCallMatcher getMatcher();



    public abstract HttpCallCustomError getCustomError();

  }



  /** A Builder which allows building immutable CustomHttpErrors object. */

  public static class Builder {



    private List<MatcherAndError> matchersAndLogs = new ArrayList<MatcherAndError>();



    public CustomHttpErrors build() {

      return new CustomHttpErrors(this.matchersAndLogs);

    }



    /** Adds a matcher to log the provided string if the error matches a particular status code. */

    public void addErrorForCode(int statusCode, String errorMessage) {

      HttpCallMatcher matcher = (req, resp) -> resp.getStatusCode() == statusCode;

      this.matchersAndLogs.add(MatcherAndError.create(matcher, simpleErrorMessage(errorMessage)));

    }



    /**

     * Adds a matcher to log the provided string if the error matches a particular status code and

     * the url contains a certain string.

     */

    public void addErrorForCodeAndUrlContains(

        int statusCode, String urlContains, String errorMessage) {

      HttpCallMatcher matcher =

          (request, response) -> {

            if (response.getStatusCode() == statusCode

                && request.getUrl().toString().contains(urlContains)) {

              return true;

            }

            return false;

          };

      this.matchersAndLogs.add(MatcherAndError.create(matcher, simpleErrorMessage(errorMessage)));

    }



    private static HttpCallCustomError simpleErrorMessage(String errorMessage) {

      return (request, response) -> {

        return errorMessage;

      };

    }

  }



  // The list of HttpRequest/Response matchers and functions to generate error strings.

  private List<MatcherAndError> matchersAndLogs = new ArrayList<MatcherAndError>();



  private CustomHttpErrors(List<MatcherAndError> matchersAndLogs) {

    // Deep copy the matchersAndLogs, which allows the builder to be reused.

    for (MatcherAndError m : matchersAndLogs) {

      this.matchersAndLogs.add(m);

    }

  }



  /** @return The the first custom error for the failing request and response to match, or null. */

  public String getCustomError(HttpRequestWrapper req, HttpResponseWrapper res) {

    for (MatcherAndError m : matchersAndLogs) {

      if (m.getMatcher().matchResponse(req, res)) {

        return m.getCustomError().customError(req, res);

      }

    }

    return null;

  }

}